I mean what you're saying sounds correct... But honestly, the whole point of the original study here was testing something that sounded correct, and it proved

I mean what you're saying sounds correct... But honestly, the whole point of the original study here was testing something that sounded correct, and it proved to be incorrect. So I have the same hypothesis as you, but the original study here shows the importance in testing things regardless of what sounds correct. It's way too easy to spread overconfidence using a theory which matches passes people's people's smell test. I think this impacts mathematics education particularly acutely. Math is an area where theory rules above all else and many people working in the area apply theory to problem solving. But mathematics education is not mathematics. It is not theoretical. It is social science. Experimental evidence and testing is the way to make progress - not sitting back and thinking.